Process of treating micaceous ores



Patented Jan. 8, 1935 UNITED STATES PATENT OFFIC No Drawing.

Application June 29, 1933,

Serial No. 678,316 '4 Claims. (01. 252-8) This invention relates to the treatment 'of micaceous ores and particularly to ores of the character of vermiculite.

The general object of this invention is to provide a process of cleaning, coloring and improving exfoliation of crude micaceous ores and a further object is to provide means whereby the fine mica flakes or particles may be given either a light golden color, a light bronze color or a gray 10 or silvery color while the mica is being liberated from the gangue and exfoliated.

In accordance with my process, the vermiculite or crude ore is wet ground, that is, the crude ore is washed and ground in a grinding mill with water. Preferably I use a grinding mill consisting of a large circular pan with steel mullers running in a circular path in the pan. Such a mill as this rubs all the surfaces of the vermiculite clean. The ore is ground to a fineness depending upon the laboratory tests of the ore, certain ore requiring grinding of thirty mesh while other ore may require grinding to forty mesh to finally effect perfect liberation of the mica from the gangue and foreign minerals. This wet grinding process partially eliminates the gangue as well as the foreign matter. The Whole mass of gangue and vermiculite is now in a powdered form. The water is now decanted from the ore so that only about twenty per cent of moisture remains in the ore. This is the natural amount of moisture absorbed by the ore. Care should be taken to avoid excessive decantation or dehydration to an extent which would remove natural moisture. By leaving approximately twenty per cent of moisture in the ground ore, exfoliation I find is very greatly improved whereas if the ore is entirely de-hydrated, exfoliation is checked and the resulting product is much less valuable than where dehydration has been 40 checked at the point indicated.

The partially liberated vermiculite is now placed in a tank which is preferably in the form of a long sloping tank 16 feet in length, four feet wide and four feet deep at the lower or has two screw conveyors installed therein and extending longitudinally of the tank. In the lower end of the tank is placed an acid solution such as hereafter stated and the ore is placed within the receiving end of the tank. The ore remains in the acid solution for a period of a few moments up to twenty+four hours depending upon the character of the ore which is shown by laboratory tests and during this period the mica is given the color desired while at the same receiving end of the tank. This tank preferably time, the acidified solution secures complete liberation of the gangue from the mica.

The following acids are used for fully liberating the gangue and coloring the mica. f

A solution of potassium iodide and sodium I sulphate gives a light golden color to the mica. Potassium iodide alone gives a light bronze color, Ammonium oxalate gives a gray color, but neither sulphuric acid or hydrochloric acid colors the mica but merely leaves it with its natural silvery 10 color to the mica.

After the mass has remained in this solution for a period of from a few moments to twentyfour hours, the screw conveyors are put into motion and the mica together with the gangue are 15 carried upward over the sloping bottom of the tank out of the acidified solution. The last step of the process consists of mechanically separating the mica from the gangue by means of jigs, classifiers or/and concentrating tables of com- 20 mon and ordinary construction. At the same time plenty of wash water is used to remove all acids. The finished product is mica in afine velvet-like condition and colored according to the colors above stated.

An alternative process to that above described is as follows:

The vermiculite is ground with water to the desired fineness, the water is decanted, as previously stated, leaving about twenty per cent of 80 moisture in the ground ore. The ground ore is' then passed to mechanical separating means, such as jigs, classifiers, and ore concentrator tables so as to separate the mica from the gangue. The separated mica is then passed into the coloring 35 tank, as before described, which contains an acidified solution, as before stated, and after remaining in the coloring tank and under the action of the acidified solution for a predeterminedperiod, as before stated, the ore is removed from 40 the tank and washed to remove all chemical residue.

In the first stated process, the operation of washing and mechanical separation is combined in a singlestep and constitutes the the process. In other words, there are three steps in the process first described andfour steps in Q the process as last described. The process produces a very finely ground, velvety product having the coloration stated and 50 this product is capable of a large variety of uses. To my knowledge, thousands of dollars have been spent in searching for the process for preparing a product of this character from crude micaceous ores but no method known to me secures the result last step of 45:"

- about 20% micaceous portion of the ore to the action of a of my method. By this method or process, I separate the micaceous material from the gangue, improve exfoliation and at the same time color the small flakes or particles of mica.

The mica which is the product of my process has many uses. Thus it may be used in wall tinting, on wall paper, for the formation of gilt, bronze, grey and silver paints, for the formation of insulating boards and panels. .These are only a few of the uses for which my product is adapted.

I claim:-

1. A process of treating micaceous ores which consists in wet grinding the ores to a predetermined degree of fineness, removing a predetermined amount of water from the ground ore to leave approximately twenty per cent of moisture in the ore, submitting the ore to the action of an acid solution of predetermined strength for from a period of a few minutes to twenty-four hours, the solution being of such strength as ,to accomplish the complete liberation of the gangue from the mica without affecting exfoliation, then mechanically separating the micaceous portion of the ore from the gangue.

2.'A process of treating micaceous ores which includes the following steps:-w'ater grinding the ore to a predetermined degree of fineness, removing excess water from the ore to a degree having of water in the mass, subjecting the solution of potassium iodide and sodium sulphite,

mechanically separating the micaceous portion of the ore from the gangue, and washing the micaceous portion of the ore to remove the acid.

3. A process of treating micaceous ores which includes the following stepsz-water grinding the ore to a predetermined degree of fineness, removing excess water from the ore to a degree having about 20% of the water in the ground mass, subjecting the micaceous portion of the ore to the action of a solution of ammonium oxalate, mechanically'separating the micaceous portion of the ore from the gangue, and washing the micaceous portion of the ore to remove the acid.

4. A process of treating micaceous ores which consists in grinding the ore with water to a predetermined degree of fineness, decanting the water from the ore to a degree leaving about twenty per cent of water in the ground mass, mechanically separating the micaceous portion of the ore from the gangue, submitting the micaceous portion of the ore with whatever gangue may still remain with the micaceous portion to the action of an acidified solution of a strength not greater than will completely liberate the gangue from the mica without affecting exfoliation to thereby further separate the micaceous portion of the ore from the gangue and at the same time color the micaceous portion of the ore, and washing the micaceous portion of the ore to remove all chemical residue.

JULIUS T. STROEHLKE. 

